There are various substances which are not compatible. When they are to be used together they must be packaged separately. This can be in two or more fully separate containers, two or more separate containers that are held together by interfitting sections or by means of a tie band, or two or more compartments of a single container. The most cost effective packages are single unitary packages which have a plurality of chambers. These are the most stable in handling and use. Also, they usually will be more compact and will require less material of manufacture. However, a problem with these various packages is the uniform dispensing of the substances from each of the compartments.
One area where multiple chamber containers are useful is in packaging and dispensing pastes such as dentifrices. In dentifrice formulations there can be components that are not highly compatible. These can be basic components and acidic components that are used to produce effervescence in a dentifrice. Likewise, these can be components such as baking soda and a peroxide such as hydrogen peroxide, or an organic peroxide such as urea peroxide These components cannot be packaged in a common container. They must be kept separate until ready for use. The use of dual chamber dispensers solves the problem of keeping such components separate and in addition provides a method for dosing the approximate amount of each component. Another area of use is in dispensing adhesives such as epoxy adhesives. The two reactive components can be kept separate until the time of use. They are then dispensed and promptly used prior to reactively hardening.
The state-of-the-art of dual chamber dispensers for dentifrices is disclosed in several United States Patents. In U.S. Pat. No. 4,773,562 there is disclosed the separate storage of two components in pressurized containers. There is a common activator for these containers and a mixing chamber prior to the paste being dispensed. U.S. Pat. Nos. 5,020,694; 5,078,963; 5,332,124 and 5,335,827 are a series of patents directed to embodiments of the same dual chamber dispenser. In this dual chamber dispenser the dispensing is activated by a manual force of pushing pistons mounted on piston rods upward into dual chambers that contain the substances to be dispensed. These patents also are directed to the structure necessary to maintain the substances separate until dispensed, having the two substances converge when dispensed, the containment structure, and the refill structure. However, the dispenser in each of these patents is conceptually the same dispenser and is activated by a manual force on piston rods that is transferred to a piston in each chamber.
Dual chamber dispensers also are exemplified by the pump dispenser disclosed in U.S. Pat. No. 5,224,627. This patent discloses a dual chamber dispenser which utilizes dual bellows pumps that are activated by means of a common lever actuator. In this dispenser the components of each of the chambers is delivered in a different ratio. The pistons in this dispenser are drawn upwardly by means of a suction force in distinction to the use of piston rods that push a piston and exert a positive pressure on the paste to be dispensed.
In the present dispenser various problems with regard to the prior art dispensers are overcome. The pumping mechanism is of the suction type and can dispense essentially equal amounts of substances having different rheologies. The dispenser is more compact and easier to handle and use. In addition, less plastic is needed for each dispenser resulting in an environmental saving. Further, since compact refill cartridges are used, the plastic usage is further decreased. The base and the pumping head are reused with only the cartridges disposed of after the contents have been depleted.
The present pump dispenser also has a unique technique for maintaining the two streams of substances being dispensed separate until use. The closure is a slit membrane closure which keeps each stream that is being dispensed separate. There is no cross-contamination of one substance with another. In a preferred embodiment each stream exists through a separate slit opening in the membrane. After dispensing the exterior surface of the membrane, closure can be cleaned if necessary. This can be done by cleaning the exterior surface.
This present multi-chamber dispenser solves these many problems. It is an advance in the art of multi-chamber dispensers, and particularly multi-chamber dispensers that pump substances by suction rather than by a direct force on a piston, such as through the use of an arrangement of a piston rod directly acting on a piston.